JPH07169091A - Metallized azoether-based pigment for optical recording layer - Google Patents

Abstract

PURPOSE: To stabilize the recording information on a photo CD disk over a long period of time by using the metallized azoether based dyestuff which is a specific element, as the dyestuff to be incorporated into a recording layer. CONSTITUTION: The metallized azoether based dyestuff contains an azo group coupling a substd. 3-hydroxy-pyridine nucleus to a phenyl nucleus having an alkoxy or thioether substituent in the second position. The process for prepn. is executed by first alkylating 2-hydroxy-4-nitroaniline by org. halide having an R<7> substituent in DMF or acetone by using potassium carbide as a base, then forming an alkoxyaniline deriv., thereby synthesizing the dyestuff. The resulted deriv. is azotized to couple the substd. 5-bromo-3-pyridinol. Bromine is substd. with sulfinate to form 5-alkylsulfonyl-6-(2-alkoxy-phenyl azo)-3- puridinol. The metallized azoether based dyestuff is obtd. by metallizing the same with a bivalent metal salt.

Description

Detailed Description of the Invention

[0001]

This invention relates to dyes. The dyes are useful in optical recording layers and elements.

[0002]

2. Description of the Related Art Optical recording materials for storing information are known. One of the currently predominant optical storage forms of information is a compact disc or CD. Digital information is stored in the form of marks or by pits with low specular reflectance on a reflective background.
In this format, the optical information is read-only memory or R
Mostly in the form of OM. Optical information is usually not recorded in real-time, but rather manufactured by press molding. In a typical process, first an optical recording substrate is press molded with a master containing the digital information to be reproduced. Then, a reflective layer is coated on the information thus formed, and subsequently, a protective layer is coated if necessary. A region including the deformed portion or the pit has a lower specular reflectance than a region including no such deformed portion.

It is desired to manufacture an optical recording medium which, when recorded in real time, produces the same recording as a CD-ROM when read. Read-out is done at about 780 nm. In this way information can be added to the CD and the CD can be used in a conventional CD player.

A recently disclosed device of this type is the so-called "Photo CD". In this apparatus, first of all, conventional photographic film is processed in the usual manner. The image obtained from the film is then digitized and the digital information is recorded on an optical recording material in a CD readable form. Then, C on the normal TV screen
The image can be reproduced by a D-type player. Since the Photo CD is not recorded to its full capacity in one use or played back only once, it requires a large number of recording and playback capacities over a long period of time. As described above, a recording material having extremely high stability is required.

One method of forming recordable elements similar to conventional injection press mold CD elements is to provide on a support:
This is a method of sequentially providing a dye layer and a reflective layer that absorb recording radiation and cause a necessary change in regular reflectance. It is said that the recording layer is irradiated with a recording beam through the support to deform the surface of the heat-deformable support adjacent to the surface of the recording layer and to change one or more dyes to reduce the regular reflectance. The recording layer is heated to the extent that Materials of this type are described in U.S. Pat. No. 4,940,618, European Patent Application 0,353,393 and Canadian Patent Application 2,005,520.

[0006]

There are stringent requirements for useful commercial materials of the type described in these documents.
One of these requirements is that the recorded information on the Photo CD disc is stable for a long period of time. Therefore, materials for Photo CD discs need to have very high photostability.

[0007]

The present invention provides a metallized azo-ether dye containing an azo group having a substituted 3-hydroxy-pyridine nucleus attached to a phenyl nucleus having an alkoxy or thioether substituent at the 2-position. It is provided.

The present invention also comprises, in order, a light transmissive support,
Also provided is an optical recording element comprising a recording layer containing a dye and a light reflective layer, the dye being a metallized azo-ether based dye according to the present invention.

The invention further provides a method for recording optical information, which in turn comprises an optical recording element comprising a light transmissive support and a recording layer containing a metallized azo-ether dye according to the invention. A method is also provided that includes the steps of: forming a pattern of different refractive index in the element by focusing an information modulated laser beam on the recording layer.

A typical metallized azo-ether dye of the present invention is represented by the following general formula (I).

[0011]

[Chemical 1]

In the above formula, R represents alkyl having 1 to 10 carbon atoms, amino, alkylamino, substituted or unsubstituted benzylamino, and R ¹ is hydrogen or 1 carbon atom.
~ 6 alkyl, R ² and R ⁴ are each independently hydrogen, alkyl having 1 to 6 carbon atoms, halogen,
SO ₂ R ⁸ or SO ₂ NR ⁹ R ¹⁰ (however, R ⁸ and R ⁹
And R ¹⁰ are each independently alkyl having 1 to 10 carbon atoms, substituted or unsubstituted benzyl, and 6 to 1 carbon atoms.
Represents 0 aryl or heteroaryl having 5 to 10 carbon atoms), R ¹ and R ² or R ³ and R
⁴ can form an aromatic ring with the atom to which they are attached, R ³ and R ⁶ are each independently hydrogen,
Represents alkyl or halogen having 1 to 4 carbon atoms,
R ⁵ is an electron-withdrawing group, R ⁷ is a carbon atom number of 1 to 6
Alkyl, C3-6 alkenyl, substituted or unsubstituted benzyl, C6-10 aryl, C5-10 heteroaryl, C6-10 hetero Arylmethyl or-(CH
₂ ) _n Y (where n is an integer from 1 to 5 and Y is cyano or COOR ⁸ ), X represents oxygen or sulfur, and M is a divalent metal ion.

The electron-withdrawing group of R ⁵ is represented by Lange's Ha
ndbook of Chemistry, 14th Edition (James A. Dean, McGraw Hill)
Co., 9.1-9.7, 1992) and has a negative Hammett sigma value. The electron withdrawing group is nitro, cyano, SO ₂ R ⁸ or SO ₂ NR ⁹
It is preferably R ¹⁰ (provided that R ⁸ , R ⁹ and R ¹⁰ are as described above).

In the above, hetero-means thienyl and furyl, and aromatic ring means isoquinoline. Alkyl can be a straight-chain or branched-chain group having up to 10 carbon atoms, for example methyl, ethyl or isopropyl. Alkoxy can be, for example, ethoxy or butoxy. Aryl can be, for example, phenyl, aminophenyl or propionylaminophenyl. Heteroaryl can be 2-thienyl. Various substituents may be bonded to these groups. For example, an alkyl, aryl, heteroaryl, alkenyl group is one or more alkoxy,
Alkoxycarbonyl, aryloxy, aryloxycarbonyl, carbamoyl, sulfamoyl, acylamino, sulfamoylamino, halogen, ureido,
It may be substituted with hydroxy, carbamoyloxy, alkoxycarbonylamino, cyano, thiocyano or carboxy groups.

The above M includes various divalent metals. Such metals are copper, zinc or nickel and other metals known to improve writability and impart a sufficient index of refraction.

Representative compounds included in Structural Formula I are set forth in Table 1 below. Here, M represents nickel.

[0017]

[Chemical 2]

[0018]

[Chemical 3]

[0019]

[Chemical 4]

[0020]

[Chemical 5]

[0021]

[Chemical 6]

First, the dye of the present invention comprises 2-hydroxy-4.
-Nitroaniline is synthesized by alkylation with an organic halide bearing the above R ⁷ substituent in DMF or acetone using potassium carbonate as a base to form an alkoxyaniline derivative. The resulting derivative is diazotized to couple the substituted 5-bromo-3-pyridinol. Bromine is replaced with sulfinate to form 5-alkylsulfonyl-6- (2-alkoxy-phenylazo) -3-pyridinol. This is metallized with a divalent metal salt. In the following, preparation examples are described to explain the general method in more detail.

[0023]

EXAMPLES Table 1, Preparation of No. 11 Compound First, 2-hydroxy-4-nitroaniline (8 g) was charged with DMF (80 ml), potassium carbonate (8.7 g) and potassium iodide (0. 1 g) and the mixture was heated at 80 ° with stirring. Benzyl chloride (3.5 g) was added dropwise and heating was continued for 4 hours. After completion of heating, the mixture was put in ice and vigorously stirred.
After solidification of the product, it was filtered off and washed with dilute sodium hydroxide solution and then with water. The NMR spectrum of the substance after drying is 2-benzyloxy-
It was in agreement with the spectrum of 4-nitroaniline.

The 2-benzyloxy-4-nitroaniline was then diazotized with nitrosylsulfuric acid in a mixture of acetic acid and propionic acid. After 2 hours, urea was added to destroy any excess nitrous acid, and the diazo solution was treated with 2-amino-5-bromo-3-hydroxy in methanol (300 ml) containing sodium acetate (30 g). -4-Methylpyridine (6 g) was added to the solution below 5 °. [Coupling Process] After the dye formation is complete, the solution is diluted with water to give the product 2
-Amino-6- (2-benzyloxy-4-nitrophenylazo) -5-bromo-3-hydroxy-4-methylpyridine was filtered off.

The above bromo compound was added to DMF (100 m
l) dissolved in sodium methanesulfinate (2 g)
And the mixture was stirred for 5 hours. The mixture was isolated by pouring it into water containing sodium nitrate (20 g) and filtering off the precipitated material. The NMR spectrum of the dye substance after drying was in agreement with the above structural formula.

The dye was added to methanol (60 ml) and nickel acetate (0.63 g) was added in portions with stirring and the solution was heated to gentle reflux for 30 minutes. The solution was allowed to cool and the product was filtered off. The absorption maximum in acetone was 613 nm, and the extinction coefficient was 9.23 × 10 ⁴ .

Compounds 8, 10, 15, 16 and 2 of Table 1
Other dyes except 4 were prepared by the same procedure. For these five compounds, the first step of the above general procedure was modified. That is, the remaining steps of the above general procedure were performed after preparing the thioether and ether substituted amine compounds by procedures well known to those skilled in the art.

The optical recording element of the present invention has a metallized azo-ether dye recording layer on a light transmissive, typically grooved support with a light reflective layer on the light absorbing layer. Take the structure that you have. A protective layer is provided on the light reflecting layer. The preferred embodiment is a writable compact disc (CD)
Is. The write and read lasers are of the laser diode type and operate in the infrared range 775-830 nm.

Recording is accomplished by focusing a laser beam modulated with information (alphanumeric or image) onto the azo-ether dye recording layer. The result is a pattern with varying specular reflectance of the element. This pattern constitutes recorded information. This pattern appears as a reflectance modulation pattern that is converted back into the recorded information by the playback electronics when scanned by the read laser. In the preferred CD format, seven elements
Write with a diode laser emitting at 75-800 nm and read with a diode laser emitting at 775-800 nm. In this CD mode, the real part of the complex refractive index (N) of the light absorption layer before writing measured with a 788 nm light source is 1.8 or more and the imaginary part (k) thereof is 0.1 or more.
It is preferable to select the metallized azo-ether dye so that it is 5 or less.

The support may be any transparent material that meets the mechanical and optical requirements. Generally, the support is pre-grooved with a groove depth of 20 to 2
50 nm, groove width 0.2 to 1 μm, pitch 1 to
2 μm. The preferred material is polycarbonate. Other useful materials include glass, polymethylmethacrylate and other suitable polymeric materials.

The optical recording element of the present invention is made by spin coating a metallized azo-ether dye alone or with one or more other dyes or additives from a suitable solvent onto a transparent support. To do. For coating, the metallized azo-ether dye with or without additives is dissolved in a suitable solvent and solvent 100 is added.
The amount of the dye per volume part is 20 parts by weight or less. Then
A metal reflective layer is coated on the dye recording layer of the element under reduced pressure by resistance heating or sputtering, and finally a protective resin is coated thereon.

The coating solvent for the dye recording layer is
The choice should be such that the effect on the support is minimal. Useful solvents include alcohols, ethers, hydrocarbons, halogenated hydrocarbons, cellosolves, ketones. Examples of solvents include methanol, ethanol, propanol, pentanol, 2,2,3,3-tetrafluoropropanol, tetrachloroethane, dichloromethane, diethyl ether, dipropyl ether,
Examples thereof include dibutyl ether, methyl cellosolve, ethyl cellosolve, 1-methyl-2-propanol, methyl ethyl ketone, 4-hydroxy-4-methyl-2-pentanone, hexane, cyclohexane, ethylcyclohexane, octane, benzene, toluene and xylene.
Other solvents include water and dimethyl sulfoxide. Hydrocarbon-based and alcohol-based solvents are preferred because they have the least effect on the preferred polycarbonate-based support. It is also possible to use solvent mixtures.

The reflective layer may be any metal layer commonly used as a reflective layer in optical recording layers. Useful metals can be vacuum evaporated or sputtered, gold,
It can include silver, aluminum, copper and alloys of such metals.

The protective layer on the reflective layer is also commonly used in this field. U as a useful material
V-curable acrylates may be mentioned. For more information on protective layers, see James C. et al. Fleming
Of "Optical Recording in Or
ganic Media: Thickness Ef
"Facts" (Journal of Imaging
Science, Vol. 33, No. 3,198
May, June 9, pp. 65-68).

Elements of the invention are described in US Pat. No. 4,940,
It may have a recorded ROM area as described in the '618 specification. The surface of the support is described in US Pat.
It may have a separate heat deformable layer as described in 0,388. Other patents relating to recordable CD-type elements are US Pat. Nos. 5,009,818, 5,080,946, 5,090,009, 4,577,291, and 5,075,147 and 5,079,135.

The following examples illustrate the utility of the dyes of this invention in optical recording elements.

[0037] The optical discs of Examples 2-7 Examples 2-7 were prepared according to the following procedure. By injection molding method, thickness 1.2mm, outer diameter 120
mm non-feature polycarbonate disc supports were produced with an inner diameter of 15 mm and an inner diameter of 15 mm.

To form the light absorbing layer, 1 part by weight of the selected dye was dissolved in 40 parts by volume of 2,2,3,3-tetrafluoropropanol by stirring at room temperature for 1 hour. The solution was then filtered through a 0.2μ filter. The solution was applied to the surface of the support by spin coating, and the total optical density at 671 nm is shown in Table II.
As described in. 15 at 80 ℃
Dry for minutes.

Then, a gold reflecting layer having a thickness of about 1200 Å was deposited on the entire surface of the disk by resistance heating. A lacquer (DAICURE FD-17 (trade name) manufactured by Dainippon Ink and Chemicals, Inc.) was applied on the gold layer by spin coating to a thickness of 7 to 11 μm. 300 it
UV cured for 15 seconds by H-bulb using Fusion System Cure at 0 W / 2.5 cm (1 inch) power.

To test the optical discs thus obtained, a tester consisting of an optical head equipped with a 788 nm laser, a 0.5 NA lens, phase tracking and 1/2 aperture focusing was used. Circularly polarized light was used in the optical system to reduce the laser feedback effect. Recording and reproduction were performed using the same laser at a rotation speed of 2.8 m / s. The read output was kept at 0.6 mW. Three
About 3. With a writing output of 18 mW through a 0 Kz filter.
Record a single frequency with a mark length of 5 microns, 78
Marks were formed that had a lower reflectance than the unmarked areas when tested with a light source emitting at 8 nm. The CNRs (carrier to noise ratios) obtained for these dyes when these marks were read are shown in Table II.

[0041]

[Table 1]

[0042]

The dye of the present invention has a good refractive index and excellent photostability.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kusaba Andras Kovacs New York, USA 14617, Rochester, Oak Ridge Drive 106

Claims (1)

[Claims] 1. A metallized azo-ether dye containing an azo group having a substituted 3-hydroxy-pyridine nucleus bonded to a phenyl nucleus having an alkoxy or thioether substituent at the 2-position.